<template>
<div>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
        <MyHeader @addTodo="addTodo"/>
        <MyList :todos="todos"/>
        <MyFooter 
          :todos="todos" 
          @checkAllTodo="checkAllTodo" 
          @clearAllTodo="clearAllTodo"
        />
      </div>
    </div>
</div>
</div>
</template>

<script>
    import pubsub from 'pubsub-js'
    import MyHeader from './components/MyHeader'
    import MyList from './components/MyList'
    import MyFooter from './components/MyFooter'

    export default {
        name:'App',
        components:{MyHeader,MyList,MyFooter},
        data() {
          return {
            //由于todos是MyHeader组件和MyFooter组件都在使用，所以放在App中(状态提升)
            todos:JSON.parse(localStorage.getItem('todos')) || []
          }
        },
        methods: {
          //添加一个todo
          addTodo(todoObj){
            this.todos.unshift(todoObj)
          },
          //取消or勾选一个todo
          checkTodo(id){
            this.todos.forEach((todo)=>{
              if(todo.id === id) todo.done = !todo.done
            })
          },
          //删除一个todo
          deleteTodo(_,id){
            this.todos = this.todos.filter( todo => todo.id !== id)
          },
          //全选or取消全选
          checkAllTodo(done){
            this.todos.forEach((todo)=>{
              todo.done = done
            })
          },
          //清除所有已经完成的todo
          clearAllTodo(){
            this.todos = this.todos.filter((todo)=>{
              return !todo.done
            })
          }
        },
        watch:{
          todos:{
            deep:true,
            handler(value){
              localStorage.setItem('todos',JSON.stringify(value))
            }
          }
        },
        mounted() {
          this.$bus.$on('checkTodo',this.checkTodo)
          this.pubId = pubsub.subscribe('deleteTodo',this.deleteTodo)
        },
        beforeDestroy() {
          this.$bus.$off('checkTodo')
          pubsub.unsubscribe(this.pubId)
        },
    }
</script>

<style>
  /*base*/
  body {
    background: #fff;
  }
  .btn {
    display: inline-block;
    padding: 4px 12px;
    margin-bottom: 0;
    font-size: 14px;
    line-height: 20px;
    text-align: center;
    vertical-align: middle;
    cursor: pointer;
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2), 0 1px 2px rgba(0, 0, 0, 0.05);
    border-radius: 4px;
  }
  .btn-danger {
    color: #fff;
    background-color: #da4f49;
    border: 1px solid #bd362f;
  }
  .btn-danger:hover {
    color: #fff;
    background-color: #bd362f;
  }
  .btn:focus {
    outline: none;
  }
  .todo-container {
    width: 600px;
    margin: 0 auto;
  }
  .todo-container .todo-wrap {
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
  }
</style>